Finite Element Modeling And Analysis Of Human Auditory System

Throughout the world, many people are suffered from deafness. Deafness, which may be due to many different causes, is generally of two types, conductive and sensorineural. Sensorineural deafness is due to the absence of, or destruction of, the hair cells in the cochlear which transfer acoustic signals into nerve impulses.For the conductive deafness, part or complete damage of tympanic membrane or ossicular are the main problem. The existing implantable middle ear hearing aid products are only suitable for the patients with part damage of ossicular. However, the piezoelectric Soundbridge system is suitable for all the conductive deafness, which overcomes the disadvantages of traditional hearing aids, for example, sound distortion, aberrance, feedback existing, crying, uncomfortableness, auricle skin stimulation, ear path obstruction and so on. At the same time, the cost is not very expensive and the surgical methods are not very complex, which make the patients convenient to use and change. So it is an efficient hearing aid device.Based on full understanding of the working principle of the Soundbridge system, the paper is focused on the finite element modeling and analysis of the human cochlear and carried out related work in three aspects:Firstly, on the basis of the previous research work, I created a more accurate three-dimensional finite element analysis model of basilar membrane. By the modal analysis and harmonic response analysis of the model, I have proved the travelling wave theory and calculated the sensitive position on the basilar membrane under a part of frequency.Secondly, I have created a relatively simple three-dimensional finite element analysis model of human cochlear firstly to get some parameter of oval window and prepared for building the complete model of human cochlear. I have taken into account the fluid-structure interaction during doing modal and harmonic response analysis of the model and can simulate the real dynamics of the cochlear.Thirdly, on the basis of the work of previous chapter, I have created a complete model. Through the modal and harmonic analysis, I probed into the impedance character of oval window and also did some research to the basilar membrance and the round window. All of these built a theoretical basis for the further research on Piezoelectric Soundbridge system.The full text is divided into five parts. The first part was about the background of the project, the research information of domestic and overseas and the paper's research goal and meaning and so on. In the second part, I described the human auditory system in detail and validated the travelling wave theory by using FEA. The third part was about how to build the finite element model of cochlear by analysis of oval. The forth part focused on the finite element modeling and analysis of human cochlea. The last part of the paper summarized the whole paper and gave some opinions for the next research work.